Made some good contacts over last weekend mobile/portable. Several good stateside and DX into Ukraine and S. Island New Zealand using the ATAS 120 . QTH was below Tincup pass (St. Elmo side) at 11k ft. I did have some problems though. I had reports of RF feedback into the MH 59 mic and I found others have this issue, I thought maybe some RF was coming through the sunroof. I'll just use the standard mic until I get ferrite bead set up for it.

The other thing that happened is several times I noticed after I TX and let up on the mic button the RX signal had dropped from where it had been (lower S-meter and audio) then after a few seconds it would come back up. I attributed to QSB. It has since happened at my base setup and this morning it happened again and didn't come back up. I tuned to a station that was coming in about s2 with this depressed RX condition so I turned off the radio, turned it back on and the s meter went to s9+. So something is up, either broken or a setting is off. Or, is it all QSB? Any thoughts ?

The other thing that happened is several times I noticed after I TX and let up on the mic button the RX signal had dropped from where it had been (lower S-meter and audio) then after a few seconds it would come back up.

Where do you have your AGC set? If not already, try changing to "Auto" and see if any thing changes

I am new to HF, on the air about a month and a half now. I was talking to another operator last night, who is long time HAM operator, he thought it was just band conditions. It is hard to explain but it sounds a bit different than "normal" QSB.